The measurement of the molecular gas content (or gas fraction, \(M_{\rm molgas} / (M_{\rm molgas} + M_{*})\) ) of galaxies as a function of cosmic time is crucial to understand their progress in forming stars. Specifically, the 5–10 times higher specific SFRs (sSFRs) at early cosmic times compared to local galaxies [1]} require either more substantial gas reservoirs or a higher star-formation efficiency in these galaxies. At the same time, vigorous star formation is connected with outflows that enrich the surrounding intergalactic medium (IGM) with processed chemical elements.
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